Contactless switching apparatus

ABSTRACT

A contactless switching apparatus comprised of a U-shaped magnetic base, the oppositely arranged yokes of which are made of a material with a large saturation magnetic flux density, a rotary yoke which is made of the same material as the yokes of the base and is attached to the free end of one yoke of the base, at least one concavity which is formed at the interval surface of the other yoke of the base, a magnetic piece with a saturation magnetic flux density smaller than the yokes of the base which is fixed at the concavity and a galvano-magnetro effect device which is fixed on the magnetic piece, wherein the rotary end of the rotary yoke approaches to and separates from the galvano-magnetro effect device as the rotary yoke rotates.

United States Patent Masuda et al.

[54] CONTACTLESS SWITCHING APPARATUS [72] Inventors: Noboru Masuda, Kawaguchi; Tu-

nekazu Kobayashi, Kawasaki, both of Japan [73] Assignee: Denki Onkyo Co., Ltd. [22] Filed: Dec. 8, 1970 21 Appl.No.: 96,079

[30] Foreign Application Priority Data [58] Field of Search ...338/32; 324/45, 46; 323/94 l-l; 317/235 H; 335/1; 307/309 [56] References Cited UNITED STATES PATENTS 3,537,046 10/1970 Hubrich et al ..378/32 R X [is] 3,681,736 51 Aug. 1,1972

Primary ExaminerC. L. Albritton Attorney-James E. Armstrong, Ronald Noboru Masuda et a]. and S. Cornell [57] ABSTRACT A contactless switching apparatus comprised of a U- shaped magnetic base, the oppositely arranged yokes of which are made of a material with a large saturation magnetic flux density, a rotary yoke which is made of the same material as the yokes of the base and is attached to the free end of one yoke of the base, at least one concavity which is formed at the interval surface of the other yoke of the base, a magnetic piece with a saturation magnetic flux density smaller than the yokes of the base which is fixed at the concavity and a galvano-magnetro effect device which'is fixed on the magnetic piece, wherein the rotary end of the rotary yoke approaches to and separates from the galvanomagnetro effect device as the rotary yoke rotates.

9 Clains, 7 Drawing figures P'A'TE'NTEDaus 1 I972 SHEET 2 OF 2 F'IG.6

BACKGROUND OF THE INVENTION The present invention relates to a contactless switching apparatus comprised of a rotary yoke which is attached to the free end of one yoke of the U-shaped magnetic base and a galvano-magnetro effect device which is provided at the internal surface of the other yoke, and devised so that the free end of the rotary yoke approaches to and separates from the galvanomagnetro effect device.

This type of conventional switch is disadvantageous because the magnetic flux applied to the galvano-magnetro effect device inevitably varies even though the gap between the rotary yoke and the device is slightly different since a pair of yokes of the magnetic base and the rotary yoke are made of a material with the same saturation magnetic flux density and the galvano-magnetro effect device is directly fixed to one yoke of the magnetic base and it is extremely difficult to produce apparatuses with the same output characteristic.

The present invention is intended to provide a contactless switching apparatus in a simple and inexpensive construction capable of eliminating the demerit mentioned above.

SUMMARY The present invention provides a contactless switching apparatus comprised of a U-shaped magnetic base, a pair of opposite yokes of which are made of a material with a large saturation magnetic flux density, a rotary yoke made of a material with a large saturation magnetic flux density which is rotatably mounted on the free end of one yoke of the base as the pivot and has the moving end extended so as to closely approach the interval surface of the other yoke of the base, at least one concavity which is provided at the internal surface of a yoke opposite to the rotary yoke so that the moving end of the rotary yoke closely approaches this concavity when the moving end is moved to a specified position, a magnetic piece with a saturation magnetic flux density lower than that of the yokes of the magnetic base and the rotaryyoke, a galvano-magnetro effect device such as, for example, a Hall effect device or magneto-resistance effect device which is fixed on the magnetic piece so as to be opposite to the yoke of the base on which the rotary yoke is mounted, and an external power supply and load circuit which are connected to the galvano-magnetro effect device, wherein the magnetic flux density applied to the galvanomagnetro effect device is kept constant by increasing the value of magnetic flux density flowing in the magnetic path consisting of the magnetic base and the rotary yoke to be larger than the value of saturation magnetic flux density of the magnetic piece.

BRIEF DESCRIPTION OF DRAWINGS The present invention is illustrated in detail in the accompanying drawings whereof:

FIG. 1 is a front view of a contactless switching apparatus of the present invention;

FIG. 2 is a magnified front view showing an important section of the apparatus illustrated in FIG. 1;

FIG. 3 is an internal view of the section shown in FIG. 2;

FIGS. 4 and 5 are the internal views of other embodiments of the section shown in FIG. 2; and

FIGS. 6 and 7 are the front views of other embodiments of the apparatus of the present invention.

DETAILED DESCRIPTION Referring to FIGS. 1 to 3, there is shown a contactless switching apparatus comprised of U-shaped magnetic base 10 which is formed by fixing a pair of yokes, l2 and 12, made of a material such as, for example, mild iron with a large saturation magnetic flux density to both poles N and S of magnet 11, rotary yoke 20 which is rotatably mounted on the free end, as the fulcrum, of one yoke 12 of the base and is extended so as to closely approach other yoke 12 of base 10, one concavity 30 which is provided at the lower internal surface of yoke 12' which is provided with a stepped portion and is arranged to be opposite to moving end 21 of rotary yoke 20, magnetic piece 40 which is fixed in the concavity and is made of a material such as, for example, ferrite with a saturation magnetic flux density smaller than that of yokes l2 and 12' of the base and rotary yoke 20, galvano-magnetro effect device 50 (hereinafter referred to as the device) such as a Hall effect device and a magneto-resistance effect device which are fixed on the external surface of magnetic piece 40 so that it is opposite to moving end 21 when rotary yoke 20 is lowered, and external input power supply 51 and external load 52 such as, for example, the switching circuit consisting of the transistors or vacuum tubes.

The apparatus according to the present invention is as described above. If rotary yoke 20 is turned so that its moving end 21 is lowered as illustrated with a solid line in FIG. 1, the magnetic flux is concentrated onto device 50, and if rotary yoke 20 is turned so that its moving end 21 is raised as shown with a broken line in FIG. 1, the distance or the air gap between device 50 and moving end 21 of the rotary yoke becomes large and the magnetic flux density applied to device 50 reduces. Accordingly, the magnetic flux density applied to device 50 varies with vertical movement of rotary yoke 20 and the output voltage and current of device 50 vary, thus causing load 52 to perform switching.

In this apparatus, device 50 is fixed to magnetic piece 40 with a small saturation magnetic flux density and rotary yoke 20 and yokes l2 and 12' of base 10 are made of a material with large saturation magnetic flux density; accordingly, a magnetic flux larger than the value of saturation magnetic flux density is applied at all times to magnetic piece 40 when rotary yoke 20 closely approaches device 50.

Consequently, since a magnetic flux equivalent to the value of saturation magnetic flux density flows in magnetic piece 40 whenever rotary yoke 20 closely approaches the device, the intensity of the magnetic field concentrated onto device 50 can be fixed at the value of saturation magnetic flux density of magnetic piece 40.

The apparatus according to the present invention is advantageous because the output characteristic of device 50 can be uniform even though the gap between device 50 and moving end 21 of rotary yoke 20 varies and the magnetic flux which is concentrated varies with each apparatus.

Hereupon it is desirable to arrange magnetic piece 40 so that the attaching surface is put in the concavity deeper than opening end 31 of the concavity 30 as shown in FIG. 2. Thus, the gap between yoke 12' of base and moving end 21 of rotary yoke becomes small until moving end 21 of the rotary yoke passes through opening end 31 of the concavity when the rotary yoke lowers from the position indicated with the broken line to the position indicated with the solid line in FIG. 1 and most of the magnetic flux from rotary yoke 20 flows in yoke 12'. When moving end 21 passes by opening end 31, the magnetic flux from rotary yoke 20 is concentrated onto magnetic piece 40 and therefore the magnetic flux applied to device 50 can' be suddenly varied. Thus, the apparatus is advantageous because it can be instantaneously and accurately switched since the output characteristic or the switching characteristic of device 50 can be made efficient.

With the above arrangement, the rise characteristic of the output voltage can be improved if device 50 is the Hall effect device and high rise characteristic can be given to the resistance variation of the device if the device is the magneto-resistance effect device.

It is desirable to provide grooves 41 which interset at a right angle to the rotating direction of rotary yoke 20 at the upper and lower positions of device 50 on magnetic piece 40 as shown in FIG. 2 and 3.

Being thus arranged, the magnetic flux flowing in rotary yoke 20 is shut out by groove 41 so that it does not affect device 50 even though moving end 21 of rotary yoke 20 closely approaches magnetic piece 40 and therefore the magnetic flux can be great only when moving end 21 of rotary yoke 20 accurately approaches device 50.

If groove 41 is thus provided, excellent rise characteristic can be given to the output voltage and current of device 50.

Furthermore, it is desirable to make magnetic piece 40 of a material with a specific magnetic permeability larger than that of yoke 12' of base 10 such as, for example, ferrite if yoke 12 is made of mild iron.

Thus, the magnetic flux flowing in rotary yoke 20 can be suddenly concentrated onto magnetic piece 40 when moving end 21 of rotary yoke 20 passes by opening end 31 of the concavity in the case that the apparatus is constructed so that opening end 31 of the concavity protrudes from magnetic piece 40 as shown in FIG. 2; therefore the apparatus in this embodiment is advantageous because the rise characteristic of the output characteristics of device 50 can be improved.

In said embodiment, if insulation layer 32 is provided between the upper internal surface of concavity 30 and magnetic piece 40 as shown in FIG. 2, magnetic piece 40 can be magnetically separated from yoke 12' of base 10; accordingly, the apparatus of this embodiment is advantageous because the magnetic flux flowing in magnetic piece 40 can be effectively applied to device Groove 41 needs not always be provided at vertical both sides of device 50 as shown in FIG. 3 and it is enough to provide one groove between opening end 31 of concavity 30 and device 50 as shown in FIG. 4 so that moving end 21 of rotary yoke 20 passes by the groove when the rotary yoke turns.

However, when it is important to suddenly change the magnetic flux density applied to device 50, it is desirable to form grooves 41 at upper and lower sides of device 50 and grooves 41' at right andleft sides of device 50 to isolate device 50 with grooves 41 and 41 And device 50 can be arranged so that the magnetic flux is concentrated when rotary yoke 20 rises. In this case, as shown in FIG. 6, concavity 30 can be formed at the upper part of yoke 12 of base 10 and magnetic piece 40 to which device 50 is fixed can be fixedly arranged.

In addition, the number of devices 50 can be more than one; for example, one magnetic piece 40 can be provided with a plurality of devices or concavities 30 and 30 can be formed at the upper and lower parts of yoke 12 of base 10, magnetic pieces 40 and 40' can be fixed at the concavities, and devices 50 and 50' can be fixed at the magnetic pieces respectively as shown in FIG. 7.

The apparatus is advantageous because two devices 50 and 50 can be alternatively actuated with said arrangement when rotary yoke 20 rises and lowers.

What is claimed is: 1. A contactless switching apparatus comprised of a. a U-shaped magnetic base having a pair of oppositely positioned yokes of which are made of a material with a large saturation magnetic flux density; a rotary yoke made of a material with a large saturation magnetic flux density which is rotatably mounted on the free end, as the fulcrum, of one yoke of the base and is extended so that its moving end closely approaches an internal surface of the other yoke;

. at least one concavity which is provided at the internal surface of a yoke opposite to the rotary yoke of the magnetic base so that the moving end of the rotary yoke closely approaches the concavity when the rotary yoke is turned to a predetermined position;

(I. a magnetic piece which is fixed at the concavity and is made of a material with a saturation magnetic flux density smaller than that of the yokes of the magnetic base and the rotary yoke; and

e. at least one galvano-magnetro effect device which is fixed at the surface of the magnetic piece.

2. A contactless switching apparatus according to claim 1, wherein the magnetic piece is provided at the concavity so that the surface to which the device is to be attached is recessed from the opening end of the concavity.

3. A contactless switching apparatus according to claim 1, wherein at least one groove is provided at a position on the magnetic piece so that the moving end of the rotary yoke passes by the groove when the rotary yoke is turned.

4. A contactless switching apparatus according to claim 3 wherein two grooves are provided on opposite sides of the device fixed on the surface of the magnetic piece.

5. A contactless switching apparatus according to claim 1, wherein a groove which surrounds the device is provided at the magneticpiece.

6. A contactless switching apparatus according to claim 1 wherein the rotary yoke is made of the same plurality of magnetic pieces respectively provided with the devices are fixed at each of the concavities so that the magnetic flux can be alternatively concentrated onto the devices when the rotary yoke is raised and lowered.

9. A contactless switching apparatus according to claim 2, wherein an insulation layer is provided between the upper internal surface of the concavity and the magnetic piece so that said magnetic piece is magnetically separated from a yoke of the base. 

1. A contactless switching apparatus comprised of a. a U-shaped magnetic base having a pair of oppositely positioned yokes of which are made of a material with a large saturation magnetic flux density; b. a rotary yoke made of a material with a large saturation magnetic flux density which is rotatably mounted on the free end, as the fulcrum, of one yoke of the base and is extended so that its moving end closely approaches an internal surface of the other yoke; c. at least one concavity which is provided at the internal surface of a yoke opposite to the rotary yoke of the magnetic base so that the moving end of the rotary yoke closely approaches the concavity when the rotary yoke is turned to a predetermined position; d. a magnetic piece which is fixed at the concavity and is made of a material with a saturation magnetic flux density smaller than that of the yokes of the magnetic base and the rotary yoke; and e. at least one galvano-magnetro effect device which is fixed at the surface of the magnetic piece.
 2. A contactless switching apparatus according to claim 1, wherein the magnetic piece is provided at the concavity so that the surface to which the device is to be attached is recessed from the opening end of the concavity.
 3. A contactless switching apparatus according to claim 1, wherein at least one groove is provided at a position on the magnetic piece so that the moving end of the rotary yoke passes by the groove when the rotary yoke is turned.
 4. A contactless switching apparatus according to claim 3 wherein two grooves are provided on opposite sides of the device fixed on the surface of the magnetic piece.
 5. A contactless switching apparatus according to claim 1, wherein a groove which surrounds the device is provided at the magnetic piece.
 6. A contactless switching apparatus according to claim 1 wherein the rotary yoke is made of the same material as the oppositely positioned yoke of the magnetic base.
 7. A contactless switching apparatus according to claim 1, wherein the magnetic piece is made of a material with specific magnetic permeability greater than that of the yoke of the base where the concavity is formed.
 8. A contactless switching apparatus according to claim 1, said yoke opposite to the rotary yoke having upper and lower sides, wherein a plurality of concavities are provided at said upper and lower sides and a plurality of magnetic pieces respectively provided with the devices are fixed at each of the concavities so that the magnetic flux can be alternatively concentrated onto the devices when the rotary yoke is raised and lowered.
 9. A contactless switching apparatus according to claim 2, wherein an insulation layer is provided between the upper internal surface of the concavity and the magnetic piece so that said magnetic piece is magnetically separated from a yoke of the base. 